Sanitary drainage systems for buildings incorporate a network of pipes for conveying waste materials out of the building. At each point of conveyance U.S. building codes require a certain water trap containing a minimum requirement of a two inch column of water which thereby prevents the passage of foul contaminated air into buildings via the sanitary piping system. The primary reason that water seals in fixture traps connected to the sanitary pipe must be protected is that spent water discharged into the drainage system causes interaction with air at the air water interface inside the pipe. A portion of the energy from the moving water is transferred to air setting it into motion. This flow of air at the core of the pipe in vertical drainage piping and at the top of the pipe in horizontal branch piping generates a negative pressure excursion as it moves through the sanitary system. If the negative pressure exceeds the allowable limit defined by codes, water trap seal loss by siphonage will occur at an unacceptable level.
Air admittance valve devices are known (U.S. Pat. Nos. 2,461,392, 3,923,081, 4,232,706, 4,545,398, 4,867,802, 5,048,562, 5,273,068 and others) for the purpose of allowing air to enter sanitary pipe work within buildings whilst preventing the passage of contaminated air outwardly from the piping system via the device during conditions of normal use. The specifications above rely on a body formed by a vertical tube in communication with a sanitary vent pipe and atmosphere having two ends; a lower end being tubular having means for engaging a pipe, and on the axially opposite end a tubular chamber, integrally housed therein, a suitable valve sealing means substantially covering an air inlet means situated within the chamber. The sealing means is securely closed at equilibrium and against high pressure whilst automatically opening upon a vacuum within the pipe to admit air, thus causing automatic equalization of the vacuum pressure to occur preventing trap water seal loss by siphonage.
There are field installation problems associated with known venting devices that consume labor and material. As shown in FIG. 7, a vent pipe 10 has a beginning at or within close proximity of fixture trap 13 requiring ventilation. The point of beginning for a vent pipe is the same, independent of whether or not a known venting device 20 is used. Vent termination point 80, however, is thereby redirected when the venting device 20 is installed in lieu of an actual vent pipe 10 through the roof 85. The redirected termination point is the venting device 20 and is commonly located within close proximity of the fixture trap 13. Piping materials and labor are thereby reduced when compared with an actual vent pipe 10 extending through the building structure and roofing membrane 85, to the outside air. Vent pipe 10 has been eliminated through use of a known venting device 20 affixing to a redirected vent pipe having a beginning at sanitary tee fitting 11 rising vertically above waste connection 19 via pipe 15 to 90.degree. fitting 16 thus offsetting horizontally within a wall cavity. The 90.degree. fitting 16 affixes to vent pipe 17 which continues a necessary distance so as to avoid interference between the venting device 20 and water supply tubes, sink bottom, drain pop up assembly and the like. A 90.degree. fitting 18 affixes to the vent pipe 17 within a horizontal plane and further to pipe stub 21 protruding outwardly from the wall cavity. Altogether parts 16, 17, 18 and 21 comprise the redirected vent pipe. Stub out 19 forms a continuation of vertical drainage pipe 14 via the tee fitting 11, to which the fixture trap 13 is eventually installed.
As further shown in FIG. 7, the piping that comprises a drainage and vent system is required to be tested, after which the known venting device 20 is affixed to the pipe stub 21, by way of a code approved, pipe compatible joining means in which a 90.degree. pipe fitting 23 is affixed to the pipe stub 21 orienting said venting device 20 vertically. Where removability of the venting device 20 is required adapter fitting 22 is utilized in conjunction with and contiguous to the 90.degree. pipe fitting 23.
1. It is code required that known venting devices shall be removable for service or replacement. Pipe adapter fitting 22 provides removability thereof when the venting device 20 is affixed to a horizontal vent pipe stub via 90.degree. fitting 23. PA1 2. Known venting devices within the field of invention are dependent upon vertical orientation for operation. Thus a code requirement that the venting device 20 shall be affixed to the vent pipe in a vertically plumb orientation exists. When the venting device 20 is affixed to horizontal pipe stub 21, additional pipe fittings are required to maintain vertical orientation of the venting device 20. To affix a vertically oriented known venting device 20 to horizontal vent pipe 17, a 90.degree. fitting 18 or pipe stub 21 and additional pipe fittings 22 and 23 are required since many connection means disclosed in prior art for adjoining such known venting devices to a pipe do not meet applicable standards referenced with the codes. PA1 3. Where a vertical drainage pipe 14 turns horizontally at base 25 and continues, it is further code required to situate access fitting 24 proximate the base 25 for enabling accessibility to the piping system in the event of a blockage or stoppage of drainage flow. Some code jurisdictions waive requirement for actual access fitting 24 In light of the fact that the vent pipe 10 through roof 85 constitutes one such point of access to the drainage system for serviceability in the event of a drain blockage or stoppage. When the vent pipe 10 through the roof 85 is eliminated by use of the venting device 20, an actual clean-out access fitting 24 must then be installed at or near base 25 of the vertical drainage pipe 14. PA1 4. As shown in FIG. 8, because of the vertical space L occupied by radius R of 90.degree. fitting 18 and adapter fitting 22, it often becomes impractical to position a horizontally redirected vent pipe 17, via the 90.degree. fitting 18 and adapter fitting 22 adjacent the known venting device 20 housed within a receptacle, together, concealed within a wall cavity. PA1 1. as shown in FIGS. 1 and 2, providing tamper and vandal resistant operational valve means within a removable first end 10, adjacent second 41 and third end opening 45 thereby meeting applicable valve service and or replacement demands required by code; PA1 2. eliminating installation of additional pipe fittings 22 and 23 (FIG. 7) required to affix known venting device 20 to horizontal vent pipe 17 via 90.degree. fitting 18 or pipe stub 21 by way of second end 41 adjacent removable first end 10 and third end opening 45 (FIGS. 1 and 2); PA1 3. eliminating access fitting 24 (FIG. 7) by providing a reusable clean-out plug 50 (FIGS. 1 and 2) affixed to third end opening 45 for future piping system maintenance or service in the event of a drain blockage, in which the third end opening 45, is adjacent the first end 10 and second end 41; PA1 4. as shown in FIGS. 5 and 6, providing a suitable receptacle 3 with a removable cover 2, having a plurality of air openings to house the venting device 60 encased within a wall cavity, the venting device 60 connecting to horizontal vent pipe 17.